Downtime questions [BitD]

I've got a few questions to make sure I'm running downtime stuff right.

1.) are the players required to indulge in their vices? What if they have no stress?

2.) if yes to the first question and they aren't at war with another faction wouldn't this just mean they only get 1 thing they can do?

3.) if a PC helps another PC with something like a long term project to give them a +1d does that count as one of their two actions?

4.) how do you guys make your downtime stuff more engaging? With my group I feel like it's been something of after the fact or clean up check list

Like they got paid for the score. Do you pay off the Crows? Yes. Do you indulge in your vices? Yes. Rolled a 2, you now have 1 stress. What do you do with your last action? Training. Mark 1 exp. Heat level 2, roll for entanglement. A rival gang tries to move in on your turf do you spend a coin and bribe them or drop a statues with them? Spend a coin. Downtime complete